National and Labour deputy leaders Bill English and Annette King are the most favoured to take over the helm of their parties should their leaders suddenly leave politics, the latest Herald-DigiPoll survey shows.
But it also suggests that low-profile frontbencher David Parker would figure highly in any future leadership contest in Labour next term.
And National campaign manager Steven Joyce would stand a good chance in a National contest.
Prime Minister John Key and Opposition leader Phil Goff are in good health. But Mr Key has previously told the Herald he would resign if he lost the election.
There has been speculation that he would hand over to someone else part-way through a second term - though in an interview with the Weekend Herald yesterday he said he would commit to a whole term if National won.
Mr Goff has campaigned strongly and if Labour did not win, he would not be expected to resign immediately in the way former Prime Minister Helen Clark did. But he would likely step down some time in the next term.
Mr English, the Deputy Prime Minister and Finance Minister, appears to have rehabilitated his reputation as a potential leader after leading National to its historically low result of 20.9 per cent in 2002.
Among National frontrunners, he is the one most favoured to step into any breach by supporters of all parties except Act, with total support of 27.1 per cent, ahead of Mr Joyce on 18.6 per cent.
Among National supporters, Mr English is even more favoured with 32.4 per cent favouring him, 23 per cent for Mr Joyce, 17.6 per cent for Judith Collins and 10.8 per cent for Gerry Brownlee.
In Labour's case, Ms King was favoured by 21.9 per cent of voters overall as the next Labour leader. But she has also made it clear she does not want to be Labour leader.
Finance spokesman David Cunliffe is seen as ambitious for the Labour leadership, sometimes overly ambitious by his colleagues. He is supported by 16.3 per cent of general voters, next behind Ms King.
Mr Cunliffe is more favoured by National and New Zealand First supporters than Mr Parker but he is not most favoured by Labour supporters.
Among Labour supporters Ms Kings is tops with 24.5 per cent, then Mr Parker on 20.9 per cent, Mr Cunliffe on 15.8 per cent and Shane Jones on 13.8 per cent.
Waiting in the wings
If Phil Goff left politics, who would be the best Labour leader?
* Annette King 21.9 per cent
* David Cunliffe 16.3 per cent
* Shane Jones 12.7 per cent
* David Parker 11.2 per cent
If John Key left politics, who would be the best National leader?
* Bill English 27.1 per cent
* Steven Joyce 18.6 per cent
* Judith Collins 15.7 per cent
* Gerry Brownlee 10.6 per cent.